The NHS has been accused of impeding the quest for lifesaving new drugs by denying many patients the chance to take part in clinical trials.

The development of novel therapies is being held back because too many hospitals are "pretty poor" at helping patients to take part in drug trials that might benefit them or others, said Dr Jonathan Sheffield, chief executive of the NHS National Institute for Health Research's clinical research network.

Health charities which between them spend £1bn a year on research say they are "frustrated" that some studies do not get enough participants, or are delayed due to low numbers, because the NHS does too little to promote them, even though an overwhelming majority of patients want to join one.

"Our ability to introduce new treatments as standard is being hampered by the slowness with which we currently recruit patients into studies, so future generations of patients are losing out," said Sheffield.

"The loss from the current situation is that new therapies take longer to be developed because there are fewer patients to form a study group," he added.

He voiced his concern after new NIHR research confirmed the scale of the problem. A team of "mystery shoppers" who visited 82 hospital sites in England found that 91% did not have any information about ongoing clinical trials in their reception or on their noticeboards or electronic screens or in leaflet displays, for example.

While 78 of the 82 sites had a receptionist, when asked who the mystery shopper should speak to if they wanted to take part in research, almost half (46%) of them did not know, directed the shopper to another part of the hospital trust or made no useful suggestions at all.

One shopper who was put through to the hospital's research and development department was told that it had too many trials going on to mention and that information about them was not available for "protection purposes". Another was asked, "What, you mean like a guinea pig?" and was directed to the human resources department. A third shopper raised the subject with a greeter, who referred him to the receptionist, who in turn directed him to the information desk. But no information was available and the shopper was then told to check out the hospital's website.

"The experience of being passed from one place to another was common," a summary of the NIHR's research says.

While half (52%) of the hospitals' websites had a dedicated research section, their usefulness varied from very good to poor and only 34% of the shoppers thought website information was useful for patients. One trust had not updated its research section since 2010, though the NIHR judged others "very informative and patient-friendly" for containing videos and links to other sites patients might find useful.

NIHR's findings are puzzling because the number of patients recruited into trials has soared from 208,200 in 2007-08 to 595,540 in 2011-12, and 99% of hospitals do at least some research.

Sharmila Nebhrajani, chief executive of the Association of Medical Research Charities, said some trials in most areas of medicine lacked patients, including dementia and neurological conditions such as Parkinson's disease.

While fewer than 1% of dementia patients get involved with a clinical trial, 20% of newly diagnosed cancer patients and 20% of children with cancer now get that chance. "The NHS needs to do quite a bit more on this, especially GPs, who need to be clear about what trials are available in their area. But patients also need to be more active and ask their hospital consultant or GP what trials there are and for their help in getting on to one," she added.

Hospitals should do more, the Department of Health said. "We want to provide the most up-to-date, innovative treatment and medicines for our patients, and clinical trials play an important part in this. Promoting clinical research is a key priority, and we want patients to have the opportunity to get involved, should they want to. It is crucial that hospitals encourage and promote participation in clinical trials to help benefit thousands of patients and make the UK a world leader in health research," said a spokesman.